The US Treasury on Friday announced sanctions on 14 Iranian individuals and entities, including the head of Iran's judiciary, Sadeq Larijani, for human rights abuses and supporting Tehran's ballistic missile programme.
Iran says the nuclear deal is not renegotiable and it will stick to the accord as long as the other signatories respect it but will "shred" the deal if Washington pulls out.
On Friday, Trump again waived sanctions against Iran that were lifted as part of the landmark nuclear deal, also known as the Joint Comprehensive Plan of Action (JCPOA).
"Despite my strong inclination, I have not yet withdrawn the United States from the Iran nuclear deal", Trump said in a statement.
Trump had privately chafed at having to once again waive sanctions on a country he sees as a rising threat in the Middle East.
China will continue playing a constructive role in maintaining and implementing the Iran nuclear deal, Chinese Foreign Minister Wang Yi said on Saturday.
Underscoring the difficulty now facing Europeans, a European diplomat, speaking under condition of anonymity, said: "It's going to be complicated to save the deal after this".
Britain, France and Germany called on Trump on Thursday to uphold the pact.
USA "could conceivably" reenter Paris Climate Agreement
Solberg said before the meeting that she'd put climate and "open world trade" on the agenda in the bilateral talks. In fact most of your energy or your electricity is produced by hydro.
Zarif has said Trump's aggressive stance on the deal and Iran generally have also violated the commitment to "refrain from any policy specifically meant to directly and adversely affect the normalisation of trade and economic relations with Iran" in the accord.
Republican Senator Bob Corker said "significant progress" had been made on bipartisan congressional legislation to "address the flaws in the agreement without violating USA commitments".
Trump has argued that Obama, a Democrat, negotiated a bad deal for the United States in agreeing to the nuclear accord.
His statement came a day after the European Union's foreign policy chief, Federica Mogherini, together with foreign ministers of France, the United Kingdom and Germany delivered a strong defense of the deal in separate statements, which were issued following a meeting with Zarif in Brussels.
But Trump warned Friday in a statement previewed by senior administration officials that that the waiver - which must be issued every 120 days to keep the sanctions from kicking back in - will be the last he issues.
This would not entail negotiations with Iran but would be the result of talks with European allies, the official said.
In August, US President Donald Trump signed into law a new package of sanctions drafted by US lawmakers. The appeal was made after the Iranian Foreign Minister met with European Union foreign ministers and European Union foreign policy chief Federica Mogherini in Brussels on Thursday.